Although fiber optic connectors can generally be most efficiently and reliably mounted upon the end portions of optical fibers in a factory setting during the production of fiber optic cable, many fiber optic connectors must be mounted upon the end portions of optical fibers in the field. As such, a number of fiber optic connectors have been specifically developed to facilitate field installation. One advantageous type of fiber optic connector that is specifically designed to facilitate field installation is the UNICAM® family of fiber optic connectors provided by Siecor Corporation of Hickory, N.C. While the UNICAM family of fiber optic connectors includes a number of common features including a common splicing technique, the UNICAM family of fiber optic connectors has several different styles of connectors including UNICAM connectors adapted to be mounted upon a single optic fiber and UNICAM connectors adapted to be mounted upon two or more optical fibers, such as the MT-RJ UNICAM connector. See, for example, U.S. patent application Ser. No. 09/108,451 filed Jul. 1, 1998 and assigned to Siecor Corporation, which describes a multifiber connector, such as an MT-RJ UNICAM connector, adapted to be spliced onto the end portions of a plurality of optical fibers. The contents of this patent application are hereby incorporated by reference in their entirety.
By way of example of an advantageous fiber optic connector designed for field installation, FIG. 1 depicts an MT-RJ UNICAM® connector 10. The connector generally includes a ferrule 12 defining one or more bores for receiving respective optical fiber stubs. The optical fiber stubs are preferably sized such that one end of the optic fiber stubs extends rearwardly beyond the ferrule. The MT-RJ UNICAM® connector also includes splice components, at least one of which defines a groove for receiving an end portion of each optical field fiber upon which the fiber optic connector is to be mounted. In order to mount the fiber optic connector upon optical field fibers, the splice components arc positioned proximate the rear end of the ferrule, such that the end portions of the optical fibers stubs that extend rearwardly beyond the ferrule are disposed within the respective grooves defined by the splice components. Thereafter, end portions of the optical field fibers can also be inserted into the respective grooves defined by the splice components. By inserting the optical field fibers into the grooves defined by the splice components until respective end portions of the optical fiber stubs and the optical field fibers make contact, optical connections can be established between respective pairs of the optical fiber stubs and the optical field fibers. In this regard, the contact between the end portions of the optical fiber stubs and the optical field fibers establishes optical continuity between respective pairs of the optical fiber stubs and the optical field fibers. The splice components can then be actuated, such as by means of a cam member 20, in order to force the splice components together and to secure the end portions of the optical fiber stubs and the optical field fiber in position within the respective grooves defined by the splice components.
In order to facilitate the connectorization of optical fibers in the field, installation tools have also been developed. For example, U.S. Pat. No. 5,040,867 to Michael de Jong et al. and U.S. Pat. No. 5,261,020 to Michael de Jong et al. describe installation tools for facilitating the connectorization of optical fibers in the field. In addition, a UNICAM® installation tool kit is provided by Siecor Corporation of Hickory, N.C., to facilitate the mounting of the UNICAM® family of connectors upon the end portions of optical field fibers in the field. An installation tool holds a number of components of the fiber optic connector including the ferrule and the splice components while the optical field fibers are inserted into the fiber optic connector and aligned with the respective optical fiber stubs.
In this regard, one conventional installation tool includes a base and a tool housing mounted upon the base. The installation tool also includes an adapter disposed within the tool housing. The adapter has a first end for engaging the fiber optic connector that is to be mounted upon the optical field fibers and an opposed second end that is a dust cap. The installation tool also includes a bias member mounted within the tool housing that engages a shoulder defined between the first and second ends of the adapter in order to secure the adapter in position within the tool housing. Typically, the bias member includes a slide member slidably connected to the tool housing and a biasing element, such as a spring, for urging the slide member into engagement with the shoulder defined by the adapter. The slide member generally includes an engagement portion having a U-shape through which the second end of the adapter extends. In addition, a conventional slide member includes a base portion disposed between the tool housing and the base and connected to the engagement portion by means of a connecting element that extends through a lengthwise extending slot defined by the tool housing. Thus, the movement of the connecting element through the slot defined by the tool housing guides the corresponding movement of the slide member in a lengthwise direction relative to the tool housing in order to engage the shoulder defined by the adapter, thereby securing the adapter in position within the tool housing.
In order to mount the fiber optic connector upon the end portions of the optical field fibers, the fiber optic connector is mounted within the installation tool. In particular, the forward end of the fiber optic connector is engaged by the first end of the adapter which, in turn, is secured within the tool housing once the slide member is biased into engagement with the shoulder defined by the adapter. The end portions of the optical field fibers are then inserted into the rear end of the fiber optic connector and the splice components are subsequently actuated, such as by being cammed together, in order to secure the optical field fibers relative to respective optical fiber stubs. The crimp tube 24 of the fiber optic connector is then crimped about the optical field fibers and, in some applications, a crimp band 26 is crimped to the strength members surrounding the optical field fibers in order to provide strain relief and otherwise protect the splice connections of the optical field fibers and the optical fiber stubs.
Once fiber optic connectors have been mounted upon the opposed end portions of the optical field fibers, the resulting fiber optic cable assembly is preferably tested end-to-end. Among other things, this testing is designed to insure that optical continuity has been established between the optical fiber stubs and respective optical field fibers. While fiber optic cables can be tested in different manners, one test involves the introduction of light having a predetermined intensity into each optical fiber stub. By measuring the light following its propagation through the fiber optic cable assembly and, more particularly, by measuring the insertion loss and back reflectance onto each optical fiber stub with a power meter, the continuity of each optical field fiber and the respective optical fiber stub can be determined. If the testing indicates that the optical fibers are not sufficiently continuous, the technician must either scrap the entire fiber optic cable assembly or, more commonly, replace one or both fiber optic connectors in an attempt to establish the desired continuity. In order to replace the fiber optic connectors, a technician generally removes, i.e., cuts off, one of the fiber optic connectors and repeats the connectorization process described above by mounting a new fiber optic connector within the installation tool and inserting the optical field fibers into the new fiber optic connector. Once the new fiber optic connector has been mounted upon the end portions of the optical field fibers, the new fiber optic connector is removed from the installation tool and the fiber optic cable assembly is again tested. If the optical fibers are still not sufficiently continuous, the fiber optic connector mounted upon the other end of the fiber optic cable assembly is typically removed and replaced as described above, prior to further testing of the resulting fiber optic cable assembly.
While fiber optic connectors and associated installation tools have been developed to facilitate the mounting of the fiber optic connectors upon the end portions of optical field fibers in the field, conventional field connectorization techniques can be quite time consuming and expensive. In this regard, since the continuity testing is not performed until after the fiber optic connectors have been completely mounted to the optical field fibers, one or both of the fiber optic connectors must typically be replaced if the testing indicates a discontinuity between the optical field fibers and the respective optical fiber stubs. This process not only requires additional time to effect the reconnectorization, but also increases the cost of the resulting fiber optic cable assembly by causing a number of potentially functional fiber optic connectors to be disadvantageously scrapped since the testing generally does not indicate which of the fiber optic connectors should be replaced. In this regard, the technician generally randomly picks one of the fiber optic connectors to replace, thereby insuring that a fiber optic connector that has been appropriately mounted upon the optical field fibers is replaced almost half of the time.
The reconnectorization of one or both ends of a fiber optic cable assembly is particularly troublesome for fiber optic cable assemblies that include a plurality of optical field fibers. In this regard, if the testing indicates a discontinuity involving any one of the optical field fibers, the fiber optic connectors mounted upon one or both ends of the fiber optic cable assembly must generally be replaced, even if the other optical field fibers and the optical fiber stubs have the desired continuity.
In order to facilitate continuity testing while the fiber optic connector remains mounted within the installation tool, Siecor Corporation previously developed a modified installation tool for a single fiber CamLite™ ST connector that permitted continuity testing. The installation tool included an adapter having opposed first and second ends, the first end of which was adapted to engage a single fiber CamLite ST connector. In order to test the continuity of the optical fiber, a laser, such as an HeNe gas laser, was provided that delivered red light to the optical fiber stub of the single fiber CamLite ST connector. More particularly, the red light was delivered via an optical fiber upon which another ST connector was mounted, This other ST connector was, in turn, inserted into the second end of the adapter such that the red light was delivered to the optical fiber stub of the single fiber CamLite ST connector. By monitoring the glow emanating from the end portion of the optical fiber stub within the fiber optic connector through a translucent connector body, the technician could determine when contact was established between the optical fiber stub and the optical field fiber based upon the dissipation of the glow, i.e., continuity is presumed to have been established once the glow dissipates. Thereafter, the cam member of the single fiber CamLite ST connector could be actuated to fix the relative positions of the optical field fiber and the optical fiber stub prior to making a final check of continuity.
While the installation tool developed by Siecor Corporation for the single fiber CamLite ST connector advantageously monitored the continuity of an optical field fiber and an optical fiber stub while the single fiber CamLite ST connector remained within the installation tool, this installation tool provided no mechanism for uncamming and repositioning the optical field fiber relative to the optical fiber stub if the continuity was inadequate after cam actuation. As such, the fiber optic connector would still have to be removed from the end portion of the optical fiber and replaced by a new single fiber CamLite ST connector if testing subsequently determined that the optical field fiber and the optical fiber stub were actually discontinuous. In addition, the modified installation tool developed by Siecor Corporation was only capable of mounting a fiber optic connector upon a single optical fiber and, more particularly, mounting a CamLite ST connector upon a single optical fiber and did not permit multifiber connectors to be mounted upon the end portions of a plurality of optical field fibers. As such, improved techniques for mounting multifiber connectors upon optical field fibers in the field and for testing the resulting fiber optic cable assembly are desired in order to reduce the overall time required for the mounting and testing procedures and to correspondingly reduce the cost of the resulting fiber optic cable assembly.